Threats to wildlife
Threatening processes are practices that are reducing or will reduce the biodiversity and ecological integrity of a regional ecosystem. For example clearing (including the cultivation of grasslands), invasive plants and animals, fragmentation, inappropriate fire regime, inappropriate grazing pressure, or infrastructure development may all be considered threatening processes.
Invasive plants and animals
Increasingly, global trade and communication are directly contributing to the introduction of plants and animals to areas where they do not naturally occur. These species taken to new environments may fail to survive but often they thrive, and they become invasive. This process, together with habitat destruction, has been a major cause of extinction of Australian native species in the past few hundred years.
Factors may include:
- an organism has been relieved of the pressures of predators or parasites of its natural distribution;
- being biologically "hardy"; for example, has short generations and a generalist diet;
- arriving in an ecosystem already disturbed by humans or some other factor.
But whatever the causes, the consequences of such invasions - including alteration of habitat and disruption of natural ecosystem processes - are often catastrophic for native species.
Invasive animals
Introduced pest animals place considerable pressure on native plants and animals. While some impacts have been well documented, the true impact of pest animals on Queensland's environment is unknown and difficult to quantify. Foxes and feral cats, which prey on native fauna, have been implicated in the decline or extinction of at least 17 native species.
Examples of invasive fauna include:
Mammals
- feral cat
- feral dog
- red fox
- feral pig
- feral goat
Amphibians
- cane toad - Introduction of amphibians from overseas brings a high risk of introducing diseases, which would devastate native populations. Examples of pathogens (disease-producing organisms) that have been brought in include the amphibian chytrid fungus. Other potential pathogens include ranaviruses.
Fish
- gambusia (mosquito fish) - Interspecific competition for resources may extend to predation, by gambusia, of eggs and larvae of endemic fishes and amphibians. In Australia, gambusia is suggested to be an imminent threat to red finned blue eye, Edgbaston goby and several endangered frog species.
Invertebrates
- feral bee - competition with glossy-black cockatoo and yellow-bellied glider for tree hollows.
Invasive plants
Weeds can degrade natural vegetation and impact on biodiversity generally.
- Rubber vine has the potential to completely destroy all deciduous vine thickets in northern Queensland, which would lead to the loss of entire unique ecosystems and the extinction of many plant and animal species.
- Dutchman's pipe, Aristolochia elegans, is an introduced ornamental vine that has become a weed in south east Queensland and northern NSW. The Richmond birdwing butterfly, one of the very few protected insect species and a feature of the subtropics, lays its eggs on a related native plant species. Female birdwings lay their eggs by preference on Dutchman's pipe, but when the larvae hatch and start to feed on the plant they die, as the introduced species is toxic to them. As Dutchman's pipe becomes more common, the Richmond birdwing, currently considered a vulnerable species, will become even rarer.
- Lantana, asparagus fern, mother of millions and guinea grass compete with the native Alectryon ramiflorus (local name: Isis tamarind)
Aquarium and other aquatic plants can carry pathogens that can devastate native populations of plants and animals.
Last updated: 23 October 2008